“Chicxulub impactor”的意思、由来-开放百科全书

The Chicxulub impactor ({{IPAc-en|ˈ|tʃ|iː|k|ʃ|ə|l|uː|b}} {{respell|CHEEK|shə-loob}}), also known as the K/Pg impactor and (more speculatively) as the Chicxulub asteroid, was an asteroid or other celestial body some {{convert|11|to|81|km|0}} in diameter and having a mass between 1.0 x 10^15 and 4.6 x 10^17 kilograms,^[3] which struck the Earth at the end of the Cretaceous period, approximately 66 million years ago,^[4] creating the Chicxulub crater. It impacted a few miles from the present-day town of Chicxulub in Mexico, after which the impactor and its crater are named. Because the estimated date of the object's impact and the Cretaceous–Paleogene boundary (K–Pg boundary) coincide, there is a scientific consensus that its impact was the Cretaceous–Paleogene extinction event which caused the death of the planet's non-avian dinosaurs and many other species.^[5]^[6]

The impactor's crater is over {{convert|150|km|abbr=off}} in diameter^[7] making it the second largest known impact crater on Earth.

Parent body

There are several competing models for the impactor's origin and its relationship to other asteroids that still exist in the Solar System. In September 2007, William F. Bottke, David Vokrouhlický, and David Nesvorný proposed an origin for the impactor in an article published in Nature. This argued that a collision in the asteroid belt 160 million years ago resulted in the Baptistina family of asteroids, the largest surviving member of which is 298 Baptistina. They proposed that the Chicxulub impactor was an asteroid member of this group, referring to the large amount of carbonaceous material present in microscopic fragments at the site, suggesting that it was a member of a rare class of asteroids called carbonaceous chondrites, like Baptistina. According to Bottke, the Chicxulub impactor was a fragment of a much larger parent body about {{convert|170|km|mi|abbr=on}} across, with the impacting body being around 60 km (40 mi) in diameter.

However, in 2011 new data from the Wide-field Infrared Survey Explorer revised the date of the collision which created the Baptistina family to about 80 million years ago, casting doubt on the hypothesis, as typically the process of resonance and collision of an asteroid takes many tens of millions of years.^[8]

Other work has associated the asteroid P/2010 A2, a member of the Flora family of asteroids, as a possible remnant cohort of the Chicxulub impactor.^[9]

See also

References

1. ^Nicholas M. Short, Sr., Crater Morphology Some Characteristic Impact Structures {{Webarchive|url=https://web.archive.org/web/20120204072914/http://rst.gsfc.nasa.gov/Sect18/Sect18_4.html# |date=2012-02-04 }} at nasa.gov, accessed January 2013
2. ^The article by Nicholas M. Short, Sr. appears to have moved, but the image above does not appear to have moved with it. See [https://fas.org/irp/imint/docs/rst/Sect18/Sect18_4.html Crater Morphology Some Characteristic Impact Structures] at fas.org, Accessed December 9, 2015.
3. ^{{cite arxiv|last1=Durand-Manterola|first1=H. J.|last2=Cordero-Tercero|first2=G.|title=Assessments of the energy, mass and size of the Chicxulub Impactor|year=2014|eprint=1403.6391|class=astro-ph.EP}}
4. ^{{Cite news|title = Dinosaur extinction: Scientists estimate 'most accurate' date|url = https://www.bbc.co.uk/news/uk-scotland-glasgow-west-21379024|website = BBC News|accessdate = 2015-10-28|date = 2013-02-08}}
5. ^{{Cite web|title = International Consensus — Link Between Asteroid Impact and Mass Extinction Is Rock Solid|url = http://www.lpi.usra.edu/features/chicxulub/|website = www.lpi.usra.edu|accessdate = 2015-10-28}}
6. ^{{Cite journal|url=http://eesc.columbia.edu/courses/w4937/Readings/Schulte.etal.2010.pdf |title=The Chicxulub Asteroid Impact and Mass Extinction at the Cretaceous-Paleogene Boundary |last=Schulte |first=Peter |date=March 5, 2010 |journal=Science |doi=10.1126/science.1177265 |pmid=20203042 |access-date=2015-06-25 |volume=327 |issue=5970 |pages=1214–8 |deadurl=yes |archiveurl=https://web.archive.org/web/20150625001637/http://eesc.columbia.edu/courses/w4937/Readings/Schulte.etal.2010.pdf |archivedate=June 25, 2015 |bibcode = 2010Sci...327.1214S }}
7. ^{{Cite Earth Impact DB | name = Chicxulub | accessdate = December 30, 2008 }}
8. ^Tammy Plotner, Did Asteroid Baptistina Kill the Dinosaurs? Think other WISE... in Universe Today (2011) at universetoday.com
9. ^[https://www.reuters.com/article/2010/02/02/us-space-asteroid-idUSTRE61154120100202 "Smashed asteroids may be related to dinosaur killer"] Reuters, February 2, 2010